The research proposal focusses on both in vitro and in vivo methods of assessment of the role of drugs on aqueous humor formation. In vitro: the isolated ciliary epithelium of the albino or pigmented rabbit eye will be used to determine a) whether the response to adrenergic agents is affected by ganglionectomy, b) to determine the responses to pure beta-adrenergic compounds and their antagonists, c) to determine the effects of pretreatment in vivo with adrenergic agents, where a refractoriness to drugs is found, and to identify whether this refractoriness is reflected in the response of the isolated ciliary epithelium to adrenergic drugs, d) to determine the effects of various metabolic inhibitors on the normal and adrenergic-stimulated secretion and permeability of the ciliary epithelium and e) to measure bicarbonate fluxes across the ciliary epithelium as a function of ambient CO2, pH and HCO3 concenrations as well as under the influence of adrenergic drugs. In vivo: a) determine drug effects on pseudofacility and aqueous humor formation rate in the living albino and pigmented rabbit eye, b) measure outflow facility, pseudofacility and intraocular pressure in conscious rhesus monkeys as a function of drugs, age and drug response with age, c) determine the solute permeability characteristics of the ciliary epithelium in the aniridic rhesus monkey eye, d) measure blood flow through normal and ganglionectomized eyes, as influenced by drugs and correlate with intraocular pressure, and e) determine the effects of water soluble compounds extracted from marihuana in rabbit and monkey eyes.